During the operation of the centrifugal pump, various failures will inevitably occur. Below we will explain the 6 major centrifugal pump problems and solutions.
1. Bearing heat
>>>Reason
(1) Poor lubrication, excessive or insufficient amount of oil, and poor oil quality
(2) The pump shaft and the motor shaft are not concentric
(3) The rotor is unbalanced
(4) The vibration of the unit exceeds the standard
(5) Bearing damage
>>>Solution
(1) Check oil quality and oil quantity, increase or decrease oil quantity appropriately or replace with new qualified lubricating oil
(2) Correct the concentricity of the two axes to meet the requirements (standard)
(3) Check the unbalance of the rotor or run at a small flow, do dynamic balance at high speed
(4) Check whether the anchor bolts and components of the unit are loose
(5) Check whether the bearing is in good condition. Inspect and clean the bearing body
2. The centrifugal pump cannot deliver liquid
>>>Reason
(1) Air remains in the suction line or pump
(2) The inlet or outlet side piping valve is closed
(3) Using head higher than the maximum head of the pump
(4) Air leakage from the suction pipe
(5) Wrong direction of impeller rotation
(6) The suction height is too high
(7) The suction pipe is too small or blocked by debris
(8) Speed does not match
(9) The impeller is blocked by debris
>>>Solution
(1) Fill with liquid and remove air
(2) Check and open the valve
(3) Replace the pump with higher head
(4) Eliminate leakage on the inlet side
(5) Correct the rotation direction of the motor
(6) Lower the installation height of the centrifugal pump and raise the water level of the inlet pool
(7) Increase the diameter of the suction pipe to remove the blockage
(8) Adjust or replace the motor to make the speed meet the requirements
(9) Remove debris from the impeller
3. Insufficient flow head
>>>Reason
(1) Impeller damage
(2) Excessive wear of the sealing ring
(3) Insufficient number of revolutions
(4) Inlet or outlet valve not fully opened
(5) Air leaks in the suction line
(6) The pipe or impeller is blocked by debris
(7) The density of the medium does not meet the requirements of the centrifugal pump
(8) The head of the device does not match the head of the pump
>>>Solution
(1) Repair or replace the impeller
(2) Replace the sealing ring
(3) Increase the number of revolutions as required
(4) Fully open the inlet and outlet valves
(5) Seal the leak well
(6) Remove clogging debris
(7) Re-calculate or replace the motor with a suitable power
(8) Try to reduce the installation height of the pump or increase the liquid level of the pump inlet or replace the pump
4. Pump vibration and noise
>>>Reason
(1) The pump shaft and the motor shaft are not concentric
(2) The pump shaft is bent
(3) The bearing is severely worn or damaged
(4) The rotating part is out of balance
(5) Pump cavitation
(6) The pipeline or pump is blocked by debris
(7) Loose foundation bolts
(8) The opening of the inlet valve is too small
(9) There is a grinding card between the rotating part and the fixed part
(10) Insufficient foundation stiffness
>>>Solution
(1) Correction alignment
(2) Replace the shaft with a new one
(3) Replace the bearing
(4) Perform static or dynamic balance test
(5) Consult the factory
(6) Check and remove the clogging debris or add a grille to the water inlet
(7) Check and tighten the anchor bolts
(8) Open the inlet valve and adjust the outlet valve
(9) Overhaul the centrifugal pump or adjust
(10) Increase the foundation stiffness or reinstall the pump seat
5. Motor overload
>>>Reason
(1) The pump shaft is bent
(2) Bearing wear or damage
(3) The filling section is pressed too tightly
(4) There is a grinding card between the rotating part and the fixed part
(5) The relative density of the medium increases
(6) Excessive flow
>>>Solution
(1) Replace the shaft with a new one
(2) Replace the new bearing
(3) Loosen the gland bolts or take out some of the packing
(4) Adjustment or overhaul
(5) Change the operating process
(6) Check the change of suction and discharge line pressure, adjust with outlet valve
6. Serious seal leakage or heat
>>>Reason
(1) Improper selection of sealing element materials
(2) The friction pair is severely worn
(3) Uneven fit of the dynamic and static rings
(4) The friction pair is too large and the static ring is broken
(5) Damaged O-ring
(6) The packing is too loose or too tight
(7) The installation position of the water seal ring is incorrect
(8) Excessive wear of the packing or wear of the bushing
(9) Poor packing quality
>>>Solution
(1) Explain the condition of the medium to the pump supply company, and select appropriate seals
(2) Replace the sealing parts and adjust the spring pressure
(3) Readjust the seal assembly
(4) Disassemble the whole pump and replace the static ring to make it meet the requirements of the verticality error of the shaft, and install the sealing assembly as required
(5) Replace the O-ring
(6) Properly press the packing to make it seep like sweat
(7) Align the position of the water seal ring with the mouth of the water seal
(8) Replace the packing or replace the bushing
(9) Select high-quality packing
